1. Field of the Invention
This invention relates to bed structures and more particularly to a frame structure for waterbeds.
2. Description of the Prior Art
Waterbeds have become very popular in the last several years and, as is well known, waterbed frames differ substantially from conventional bed frames due to the different structural requirements imposed thereon by the characteristics of the waterbed mattress.
In general, waterbed frames include a pedestal assembly for supporting a mattress frame. The pedestal assembly is usually in the form of an open rectangular frame having a free-standing cross-shaped support structure therein and upon which a planar platform is supported. The mattress frame is also an open rectangular structure which provides upstanding side walls for supporting the periphery of the waterbed mattress which is positioned within the mattress frame atop the planar platform of the pedestal assembly.
A waterbed mattress is normally a rectangularly shaped flexible bag of plastic material for containing water in amounts which range from approximately 50 gallons for a child's bed to about 350 gallons for a king size bed. The weight of the water along with the static and kinetic loads imposed by the water, both vertically and laterally, make it imperative that a waterbed frame be structurally sound. To meet the rather stringent structural requirements, the rectangular frame of the pedestal assembly and the rectangular structure which forms the mattress frame are made of 2 .times. 8 inch or 2 .times. 10 inch wooden planks of suitable length.
In addition to using structurally strong wooden planks, the corner joints employed to assemble the required rectangular structures are factors which must be considered.
Prior art waterbed frames are fabricated with butt joints at the corners of the rectangular frames, and the butt joints are held by hinge mechanisms which extend almost the full length of the joints. The hinges are mounted on the inwardly facing surfaces of the planks and are affixed thereto by wood screws. As is well known in the cabinetmaking art, a butt joint is the weakest joint of the type commonly used to form corners and the like. It is also well known that to use wood screws alone as fastening hardware is generally a poor practice, and is particularly poor when wood so joined is subject to stresses due to vibrations, loading and the like.
In addition to the inherent structural weakness of the prior art corner joints, such joints have other shortcomings. First, employing a hinge as described above is time consuming from the assembly standpoint and provides little or no deterrent to warpage of the wooden planks which, besides producing an unsightly structure, can loosen the wood screws which hold the hinge in place. Secondly, locating the hinges on the inwardly facing plank surfaces exposes the plastic waterbed mattress, and liner if used, to relatively sharp edges which can, and sometimes does, result in punctures and abrasive wear of those plastic items. Third, water movements produced by movements of the bed's occupants will result in undulating movement of the mattress which in turn applies uneven and erratic loading of the mattress frame which causes the corner joints to work, i.e., the planks move independently of each other. Such working of the corner joints will eventually result in the loosening of the wood screws.
Therefore, a need exists for a new and useful waterbed frame structure which overcomes some of the problems and shortcomings of the prior art.